Mesons and diquarks in a color superconducting regime

The behavior of the mesons and diquarks is studied at finite temperatures, chemical potentials and densities, notably when the color superconductivity is taken into account. The Nambu and Jona-Lasinio model complemented by a Polyakov loop (PNJL description) has been adapted in order to model them in this regime. This paper focuses on the scalar and pseudoscalar mesons and diquarks, in a three-flavor and three-color description, with the isospin symmetry and at zero strange density. An objective of this work is to underline the modifications carried out by the color superconducting regime on the used equations and on the obtained results. It has been observed that the two-flavor color-superconducting (2SC) phase affects the masses and the coupling constants of the mesons and diquarks in a non-negligible way. This observation is particularly true at high densities and low temperatures for the pions, [Formula: see text] and the diquarks [Formula: see text] whose color is [Formula: see text]. This reveals that the inclusion of the color superconductivity in the modeling is relevant to describe the mesons and diquarks near the first-order chiral phase transition.

LHC signatures of sterile neutrinos in a minimal radiative extended seesaw framework

The presence of small neutrino masses and flavour mixings can be accounted for naturally in various models about extensions of the standard model, particularly in the seesaw mechanism models. In this work, we present a minimally extended seesaw framework with two right-handed neutrinos, where the active neutrino masses are derived in the radiative regime. Using the framework it can be shown that within certain mass limits, the light neutrino mass term can approach a form that is similar to its form under type-I seesaw mechanism. Apart from this, we show that the decay width of right-handed neutrinos (produced through the decay of [Formula: see text] boson in a particle collider) is short enough to cause a sufficiently long lifetime for the particles, thus ensuring an observable displacement in the LHC between the production and decay vertices. We comment on the fact that these displaced vertex signatures thus can serve as a means to verify the existence of these right-handed neutrinos in future experiments. Lastly, we line up the possibility of our future work where the vertex signatures of particles greater than the mass of [Formula: see text] boson can be worked upon.

Status of searches for electroweak-scale supersymmetry after LHC Run 2

The second period of datataking at the Large Hadron Collider (LHC) has provided a large dataset of proton–proton collisions that is unprecedented in terms of its centre-of-mass energy of 13 TeV and integrated luminosity of almost 140 fb[Formula: see text]. These data constitute a formidable laboratory for the search for new particles predicted by models of supersymmetry. The analysis activity is still ongoing, but a host of results on supersymmetry had already been released by the general purpose LHC experiments ATLAS and CMS. In this paper, we provide a map into this remarkable body of research, which spans a multitude of experimental signatures and phenomenological scenarios. In the absence of conclusive evidence for the production of supersymmetric particles we discuss the constraints obtained in the context of various models. We finish with a short outlook on the new opportunities for the next runs that will be provided by the upgrade of detectors and accelerator.

On the evaluation of the Gottfried sum and d̄−ū asymmetry with the use of the TMM method

In this paper, we obtain the integrated flavor asymmetry of the sea quarks in the proton, [Formula: see text], with the help of the truncated moments approach elaborated in our previous papers. We use the difference between the light sea-quark distributions [Formula: see text] extracted from Drell–Yan (DY) NuSea/E866 measurements of the cross-section ratio [Formula: see text] and from the recent global analysis of deep inelastic scattering (DIS) [Formula: see text] data incorporating the reanalyzed neutron structure function. In our analysis, we also include the most recent DY data from the Fermilab SeaQuest/E906 experiment.

Anisotropic minimally interacting dark energy models with cosmic strings and a massive scalar field

This paper deals with the construction of locally rotationally symmetric (LRS) Bianchi type-II (B-II) cosmological models obtained by solving Einstein field equations coupled with an attractive massive scalar field (MSF) when the source of gravitation is the mixture of cosmic string cloud and anisotropic dark energy (DE) fluid which are minimally interacting. We have obtained exact cosmological models by using (i) shear scalar is proportional to the scalar expansion of the space–time and (ii) a power-law relation between the average scale factor of the universe and the scalar field. Our models represent string cosmological model and DE model in the presence of MSF. Using our model, we determine cosmological parameters such as energy densities, deceleration parameter, statefinders and equation of state parameter. We, also, present the tension density and energy density of the string. We discuss the physical aspects of these cosmological parameters. It is observed that our models represent accelerated expansion phenomenon of our universe as confirmed by Supernova Ia experiment.

A new class of holographic dark energy models in LRS Bianchi Type-I

In this paper, we examine the LRS Bianchi-type-I cosmological model with holographic dark energy. The exact solutions to the corresponding field equations are obtained by using the generalized hybrid expansion law (HEL). The EoS parameter [Formula: see text] for DE is found to be time-dependent and redshift-dependent and its exiting range for derived model is agreeing well with the current observations. Here, we likewise apply two mathematical diagnostics, the statefinders ([Formula: see text]) and [Formula: see text] plan to segregate HDE model from the [Formula: see text]CDM model. Here, the [Formula: see text] diagnostic trajectories are good tools to classify the dynamical DE model. We found that our model lies in both thawing region and freezing region. We also construct the potential as well as dynamics of the quintessence and tachyon scalar field. Some physical and geometric properties of this model along with the physical acceptability of cosmological solution have been discussed in detail.

Casimir effect with one large extra dimension

In this work, I study the Casimir effect of a massive complex scalar field in the presence of one large compactified extra dimension. I investigate the case of a scalar field confined between two parallel plates in the macroscopic three dimensions, and examine the cases of Dirichlet and mixed (Dirichlet–Neumann) boundary conditions on the plates. The case of Neumann boundary conditions is uninteresting, since it yields the same result as the case of Dirichlet boundary conditions. The scalar field also permeates a fourth compactified dimension of a size that could be comparable to the distance between the plates. This investigation is carried out using the [Formula: see text]-function regularization technique that allows me to obtain exact expressions for the Casimir energy and pressure. I discover that when the compactified length of the extra dimension is similar to the plate distance, or slightly larger, the Casimir energy and pressure become significantly different than their standard three-dimensional values, for either Dirichlet or mixed boundary conditions. Therefore, the Casimir effect of a quantum field that permeates a compactified fourth dimension could be used as an effective tool to explore the existence of large compactified extra dimensions.

Noninertial effects on a composite system

In this paper, we investigate the relativistic dynamics of a fermion–antifermion pair holding through Dirac oscillator interaction in the rotating frame of [Formula: see text]-dimensional topological defect-generated geometric background. We obtain an exact energy spectrum for the system in question by solving the corresponding form of a fully covariant two-body Dirac equation. This energy spectrum depends on the angular velocity [Formula: see text] of uniformly rotating frame and angular deficit [Formula: see text] in the geometric background. Our results show that the effects of [Formula: see text] on each energy level of the system are not same and the [Formula: see text] impacts on the strength of interaction between the particles. Furthermore, we observe that it seems to be possible to actively tune the dynamics of such a fermion–antifermion system, in principle.

Induced surface and curvature tension equation of state for hadron resonance gas in finite volumes and its relation to morphological thermodynamics

Here, we develop an original approach to investigate the grand canonical partition function of the multicomponent mixtures of Boltzmann particles with hard-core interaction in finite and even small systems of the volumes above 20 fm3. The derived expressions of the induced surface tension equation of state (EoS) are analyzed in detail. It is shown that the metastable states, which can emerge in the finite systems with realistic interaction, appear at very high pressures at which the hadron resonance gas, most probably, is not applicable at all. It is shown how and under what conditions the obtained results for finite systems can be generalized to include into a formalism the equation for curvature tension. The applicability range of the obtained equations of induced surface and curvature tensions for finite systems is discussed and their close relations to the equations of the morphological thermodynamics are established. The hadron resonance gas model on the basis of the obtained advanced EoS is worked out. Also, this model is applied to analyze the chemical freeze-out of hadrons and light nuclei with the number of (anti-) baryons not exceeding 4. Their multiplicities were measured by the ALICE Collaboration in the central lead–lead collisions at the center-of-mass energy [Formula: see text] TeV.

Generation of Carroll–Field–Jackiw term in the functional integral approach within Horava–Lifshitz z = 3 CPT-violating QED

In this paper, we apply the functional integral methodology to induce the Carroll–Field–Jackiw (CFJ) term in Horava–Lifshitz [Formula: see text] CPT-violating QED, where Lorentz and CPT breaking for fermion and photon sectors is introduced, and show that the CFJ term is finite but undetermined.